Neutrophils recruited by NKX2-1 suppression via activation of CXCLs/CXCR2 axis promote lung adenocarcinoma progression

Abstract

Abstract Background: Lung adenocarcinoma (LUAD) progression is dependent on the immune tumor microenvironment through paracrine signaling. NKX2-1 is the lineage-specific transcription factor that serves as a well-characterized pathology marker to define LUAD with progressive impact in patients. However, the involvement of NKX2-1 in modeling the tumor immune microenvironment is still unclear. Here, we demonstrated that NKX2-1-low tumors expedite tumor progression in LUAD by recruiting tumor-promoting neutrophils. Method: Single-cell RNA sequencing and Visium in situ capturing profiling were used to characterize the infiltration of neutrophils in orthotopic syngeneic tumors. Clinical relevance of NKX2-1 expression and disease status were evaluated by immunohistochemical analysis of LUAD tissue arrays and the overall survival analysis was performed by using TCGA dataset. Chemokine secretion was analyzed by chemokine array and validated by qRT-PCR. ATAC-seq was used to confirm the modulatory role of NKX2-1 on the chromatin accessibility of CXC chemokine genes. Results: NKX2-1 downregulation was observed in high-grade LUAD with increased neutrophil recruitment and infiltration. NKX2-1 knockdown promoted the expression and secretion of CXCL1, CXCL2, CXCL3, and CXCL5 in LUAD cells. ATAC-seq revealed the restrictive regulation of NKX2-1 on the promoters of CXCL1, CXCL2and CXCL5. Single-cell RNA sequencing and Visium in situ capturing revealed that the infiltrated neutrophils exhibited strong cell-cell communication through the activation of CXCLs/CXCR2 signaling with increased tumor growth and vice versa when inhibited with CXCR2 antagonist SB225002. Conclusion: This study revealed that NKX2-1 negatively regulates the infiltration of tumor-promoting neutrophils by suppressing CXCLs/CXCR2-dependent mechanisms. Hence, targeting CXCR2 in NKX2-1-low tumors is a potential antitumor therapy that may improve LUAD patient outcomes.